| 辽宁省排山楼矿区二长花岗岩成因及其与金矿化的关系 |
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| 引用本文： | 孙守恪,刘红涛,褚少雄.辽宁省排山楼矿区二长花岗岩成因及其与金矿化的关系[J].岩石学报,2012,28(2):607-618. |
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| 作者姓名： | 孙守恪 刘红涛 褚少雄 |
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| 作者单位： | 中国科学院地质与地球物理研究所,北京,100029 |
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| 基金项目： | 本文受全国危机矿山找矿资源专项综合研究项目(20089931)资助. |
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| 摘 要： | 研究区位于华北克拉通北缘东段,排山楼二长花岗岩体为一个小型的岩株,出露于排山楼韧性剪切带型金矿床的北部。岩石为不等粒似斑状花岗结构,主要由钾长石、更长石、石英、黑云母和少量角闪石构成,含有锆石、榍石、磷灰石、钛铁矿等副矿物,属于高钾钙碱性准铝质I型花岗岩。该二长花岗岩具有富钠,高Sr、Ba含量,重稀土强烈亏损和轻微的正铕异常等特殊的地球化学特征,从而推断其岩浆可能起源于加厚陆壳底部角闪岩类的部分熔融。锆石U-Pb年龄(128±1.3Ma)表明该岩体在燕山晚期白垩纪侵位。由于在排山楼矿床观察到二长花岗岩的侵位晚于控矿糜棱岩带、但岩体本身又发育了金矿化,根据本岩体与含矿韧性剪切带的密切时空关系,参照区域构造热事件与成矿作用的密切联系,认为排山楼二长花岗岩浆的侵位与控矿韧性剪切作用,可能是本区燕山晚期岩石圈伸展体系下同一构造热事件的不同侧面,因而二者应存在构造机制上的密切联系。但不排除控矿韧性断裂长期活动的可能性以及曾经有更早期次金矿化发生的可能性。
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| 关 键 词： | 排山楼金矿床 二长花岗岩 岩石成因 锆石U-Pb年龄 成因联系 |
| 收稿时间： | 2011/8/30 0:00:00 |
| 修稿时间： | 2011/11/1 0:00:00 |
Origin of the Paishanlou monzogranite in Liaoning Province and its genetic connection with gold mineralization |
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| SUN ShouKe,LIU HongTao and CHU ShaoXiong.Origin of the Paishanlou monzogranite in Liaoning Province and its genetic connection with gold mineralization[J].Acta Petrologica Sinica,2012,28(2):607-618. |
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| Authors: | SUN ShouKe LIU HongTao and CHU ShaoXiong |
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| Institution: | Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China;Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China |
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| Abstract: | The Paishanlou monzogranite stock is outcropped in the vicinity of the Paishanlou gold deposit hosted by a ductile shear zone occurred within Late Archean high-grade metamorphic sequences lying in the eastern segment of northern periphery of North China Craton. Mineralogy of the monzogranite consists principally of K-feldspars, oligoclase, quartz and biotite, with minor amphibole and trace zircon, sphene, apatite and ilmenite. The I-type monzogranite with high-K calc-alkaline attributes displays unique geochemical features including sodium enrichment relative to potassium, notably high Sr and Ba concentrations, strongly depleted heavy REE, as well as the presence of minor positive Eu anomalies on the REE patterns, suggesting that the magmas might be derived from the partial melting of amphibolitic protolithes under the P-T conditions of over-thickened continental lower crust. LA-ICP-MS zircon U-Pb dating yields absolute age of 128±1.3Ma indicating the stock was emplaced during Late Yanshanian, Cretaceous, during which a lithospheric extensional regime was prevailing in the region. As the monzogranite intrudes into the mylonite zone which are the ore-controlling structure and the granitoids develop gold mineralization. Also based on the close spatial and temporal relations between the monzogranite and ore-hosting ductile shear zones, with considering the intimate connections among regional thermal-tectonic events and mineralization, it is suggested that the emplacement of the monzogranite stock may probably genetically be related to the ore-hosting ductile shearing nearby to the south by the regional extensional tectonism during Late Yanshanian. But the possibility that the ore-control ductile fracture was active in a long period or there exists an earlier generation of gold mineralization can not be rejected. |
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| Keywords: | Paishanlou gold deposit Monzogranite Petrogenesis Zircon U-Pb age Genetic connection |
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